Re: [Jython-users] reg exp negations

[Ype K. <yk...@xs...>]

Doug,

>I'm using the re module with Jython embedded in my Java app to handle the
>pattern matching.  I'm struggling with the regular expression syntax to
>perform a negation of a pattern.  Specifically, for a date I want to allow
>DD-MMM-YY (JAN, MAR,etc for the month value) so I want my match object to
>be returned only for items that don't match this pattern.
>
> r=re.compile('[0123][0-9][-]\w{3}[-][01][0123]').search("12-DEC-02")
>//this returns a match object
>
>How can I wrapper this pattern and negate it so the failure to find the
>pattern is what is returned?
>
>I've tried variations similar to the snippet below to group and negate
>without success.
>r=re.compile('^([0123][0-9][-]\w{3}[-][01][0123])').search("12-DEC-02")
>
>I have looked at the Mastering Regular Expressions book which is some help
>but is heavily Perl slanted.  The re module documentation doesn't delve
>into my particular issue sufficiently (or I just missed it).  Any
>recommendations for additional reference resources in addition to some help
>with the current problem would be welcome.

Did you consider java's date formatter? I think it does exactly what
you want:

http://java.sun.com/j2se/1.4/docs/api/java/text/DateFormat.html

You'll have to catch the ParseException from the parse() method
to handle the failure to find the pattern.

Good luck,
Ype

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